There are many “vector-borne” infections carried by rodents which can be transferred to humans in a similar way to leptospirosis. The links on this page refer to some of the more important ones, but this is by no means a complete list. The LIC does not provide advice and support on these pathogens, nor are we responsible for the content or availability of external pages.
In addition to pathogens (bacteria, viruses, fungi) it is common to see allergic sensitivity to dust containing particles of rodent droppings or hair fragments, with symptoms resembling pollen allergy. Incidences of extreme reactions are however very rare indeed.
Pathogens carried by rodents and other small mammals
- Murine Typhus
- Murine typhus is a bacterial infection spread by lice and fleas carried by many feral species, including rodents, cats, possums, etc., though is confined to specific regions of the world and is rarely fatal. Symptoms are almost identical to leptospirosis; diagnosis is via blood testing and treatment is by antibiotics as for leptospirosis. The causative agent is the bacterium Rickettsia typhi.
- Lymphocytic Choriomeningitis
- LCM is a widespread viral disease carried predominantly by the house mouse, and contracted via contact with urine, saliva, blood and droppings. Symptoms are similar to leptospirosis but the disease is rarely fatal, and often extremely mild. As many as 30% of the general population show evidence of having contracted LCM at some point. There are significant concerns over infection during pregnancy. The virus can remain viable when dry, unlike leptospira. There is no specific treatment or vaccine available. The causative agent is the LCMV arenavirus.
- Rat-bite fever
- This is a rare bacterial infection, primarily from rats, caused by the Actinobacillus muris bacterium. It is most commonly seen in Japan, where it is called ‘sodoku’, but cases are also known in the Americas, Australia, Europe and Africa. Contracted via a bite, or by contact with infected urine or secretions from the mouth, eyes or nose of an infected animal. Symptoms include fever, chills, rash, headache, muscle pain and inflammation at a bite site. Infection is diagnosed by blood tests and treated by antibiotics. Prognosis is usually excellent.
- Plague is a viral infection by Yersina pestis (Y pestis). Historically widespread, it is now very rare except in specific areas of the world. Y pestis is associated with feral rats (though is known in other rodents and small mammals), and is spread via their fleas. Bites from infected fleas can result in bubonic or septicemic plague, both of which are treatable using antibiotics and cannot be spread from person to person. Pneumonic plague, spread by inhaling the virus, is naturally the result of close contact with an infected person or animal, but artificially is a potential bioweapon. An untreated patient with bubonic or septicemic plague may develop pneumonic plague and become infectious to others. Natural strains of Y pestis are killed rapidly by drying and exposure to sunlight (within an hour or two) – only weaponised strains have the capacity to survive airborne for long periods.
- A potentially-severe disease caused by the highly-infectious bacterium Francisella tularensis, carried by many small mammals but especially prevalent in rodents, rabbits and hares. Spread by contact with an infected animal or carcass, indirectly via tick or insect bites, or by ingestion of contaminated food or water. Symptoms include fever, chills, headaches, muscle pain, diarrhoea and weakness (note diarrhoea is not a symptom of leptospirosis). Not known to spread person-to-person. Treatment is via antibiotics, but can be fatal if not treated promptly.
- Hantavirus pulmonary syndrome
- A relatively rare but potentiall very severe viral disease spread by rodents – in the USA the primary rodent hosts are the deer mouse, the cotton/rice rat and the white-footed mouse. Infection is possible through inhalation of dust, direct contact with contaminated urine or animals and in rare cases via bites, but cannot be spread person-to-person. Symptoms inlcude fever, muscle pain, headaches, nausea and diarrhoea, chills and coughs but can be difficult to differentiate in the early stages. There is no rash or hemorrhaging. No specific medication is available – ribavirin is not effective.
- Infection from one of the group of bacteria called Salmonella, which are widespread in the environment and present in the feces of most animals, including rodents and humans. The bacteria must be ingested (typically via water contaminated by fecal matter). Illness is predominantly gastrointestinal, with diarrhoea, cramps, fever and vomiting. Most patients self-recover without medication, but often require additional fluids to counteract losses.
- Lassa fever
- A viral infection specific to West Africa, spread by the multimammate rat, resulting from the Lassa arenavirus. Infection is possible through inhalation of dust, direct contact with contaminated urine or animals, and in rare cases can be spread person-to-person.
- Hemorrhagic fever with renal syndrome (HFRS)
- A group of hantavirus infections known throughout the world but most common in Eastern Asia. Hantavirus pulmonary syndrome (see above) is a markedly different disease but caused by a closely-related virus. HFRS is carried by a number of rodents, and although can be fatal, is more often self-recovering. Intravenous ribavirin is known to be of benefit. Initial symptoms include fever, chills, headache, nausea, blurred vision and severe back and abdominal pain, progressing in severe cases to kidney failure.
- South American Arenavirus infections
- In addition to LCM, there are a number of related hemorrhagic fevers spread by direct or indirect contact with rodents in South and Central America. As with LCMV, infection is possible through inhalation of dust, direct contact with contaminated urine or animals, and in rare cases can be spread person-to-person.
Pathogens found in water (ponds, rivers etc.)
Aside from the indirect route taken by zoonoses (animal-hosted pathogens such as leptospirosis) there are of course a large number of bacterial, viral and parasitic diseases spread via water. They may be the result of natural colonies of pathogens (such as blue-green alage or cryptosporidium) or contamination of the water by animal or human waste. There are also diseases which are associated with water but not carried within it, such as malaria.
For an overview of waterborne diseases and drinking water safety, see THIS LINK.
Other vector-borne diseases of interest
- Lyme disease
- A bacterial infection spread by tick bites in many regions of the world. The bacterium in question, Borrelia burgdorferi, is a spirochete closely-related to leptospira, but is not spread by indirect exposure, and has no specific association with rodents or water. A characteristic bulls-eye spreading rash centered on the bite is the first symptom, others include the general infectious responses of fever, chills, muscle pain, headaches, etc. with untreated patients often experiencing long-term problems. Treatment is by antibiotics and is effective.